Most individuals buy and use a hair shampoo for its cleansing properties. A consumer often also desires a hair shampoo that conditions the hair. However, hair shampoos generally are formulated with highly-effective anionic surfactants that are nonsubstantive to the hair and primarily cleanse the hair. Therefore, shampoos typically neither aid in the detangling of wet hair nor condition dry hair, such as improving the manageability or styleability of hair sets.
After shampooing with an anionic surfactant-based hair shampoo, the hair normally is left in a cosmetically-unsatisfactory state because anionic surfactants not only remove the dirt and soil from the hair, but also remove essentially all of the sebum naturally present on the surface of the hair fibers. Therefore, although anionic surfactants effectively cleanse the hair, hair shampoo compositions containing anionic surfactants leave the hair with an harsh, dull and dry touch, or feel, usually called "creak", after the hair is shampooed and then rinsed with water.
Thoroughly cleansed hair is extremely difficult to comb, in either the wet or dry state, because individual hair fibers tend to snarl, kink and interlock with each other. In addition, incompletely dried hair, such as hair dried with towel, has poor brushing properties, and after complete drying, the hair does not set well. Furthermore, the combing or brushing property of the hair remains poor, and the hair has undesirable electrostatic properties in a low humidity atmosphere that causes the hair to "fly away", thereby further reducing the brushing properties of the hair. The unsatisfactory combing or brushing property of hair immediately after shampooing also causes hair damage, such as split ends or hair breakage. In addition, the natural luster and resiliency of the hair is reduced. Consequently, the overall unsatisfactory condition of shampooed hair usually necessitates a subsequent post-shampoo hair treatment with a conditioning composition to improve these undesirable physical characteristics. Conditioning compositions are designed to maximize the conditioning properties of the hair and normally are applied separately from the hair shampoo. Typically, conditioning compositions are rinses or cream-like lotions containing a cationic compound that is substantive to the hair or a silicone compound.
Therefore, consumer needs traditionally have been met by the application of a shampoo to clean the hair, followed by the application of a conditioner composition to improve wet combing and other properties. The commonly-accepted method has been to shampoo the hair, followed by rinsing the hair, and then separately applying a conditioner composition, followed by a second rinse.
While numerous shampoos that include hair conditioners have been disclosed, such combination shampoos have not been totally satisfactory for a variety of reasons. In regard to shampoo-conditioner compositions, one problem relates to compatibility problems between anionic surfactants and cationic conditioning agents. This compatibility problem has caused workers in the field to investigate other surfactants, such as nonionics, amphoterics and zwitterionics, as a total or partial replacement for the anionic surfactant in shampoos. These investigations are reflected in patents issued in the shampoo conditioner area, for example, Hewitt U.S. Pat. No. 3,849,348; Gerstein U.S. Pat. No. 3,990,991; and Sato U.S. Pat. No. 3,822,312.
Accordingly, to avoid the cationic-anionic incompatibility problem, to increase the degree of conditioning imparted to the hair and to maintain the cleaning efficiency of the hair shampoo, investigators incorporated silicone compounds into anionic surfactant-based shampoo compositions. A problem inherent in formulating a silicone-based shampoo conditioner is the phase separation and foam height depression that result when a water-insoluble silicone conditioning agent is included in an aqueous shampoo-conditioner composition. A shampoo-conditioner composition of the present invention does not require a silicone conditioning agent, thereby overcoming the phase separation and foam height problems. Surprisingly, however, a shampoo-conditioner composition of the present invention conditions the hair as well as conditioner compositions including a highly-effective silicone conditioning agent.
A particularly difficult problem encountered in formulating silicone-containing shampoo-conditioner compositions is maintaining the insoluble silicone material homogeneously suspended in the composition. A variety of materials have been proposed for use in silicone-containing conditioning shampoos for the purposes of thickening and stabilization. These materials include xanthan gum, long chain acyl derivatives, long chain amine oxides, and long chain alkanolamides.
In particular, Oh et al. U.S. Pat. No. 4,704,272 discloses shampoo compositions including an anionic surfactant, a nonvolatile silicone, a hair conditioning agent and a suspending agent. The hair conditioning agent can be a tri-long chain (C.sub.8 -C.sub.22) amine, such as tri(isodecyl)amine or tri-C.sub.13 amine. Oh et al. also teach that a suspending agent, like a xanthan gum or a long chain acyl derivative, is essential to the composition. Surprisingly, it has been found that a primary amine having a carbon chain having at least 14 carbon atoms, and sufficiently neutralized with a suitable acid, provides a stable shampoo-conditioner composition that effectively cleans and conditions the hair without the need for a silicone conditioning agent or an anionic surfactant.
Bolich et al. U.S. Pat. No. 4,472,375 discloses an aqueous hair conditioning composition comprising a volatile hydrocarbon or a volatile silicone; a nonionic thickening agent; and a quaternary ammonium salt and/or a salt of a fatty amine. The composition of Bolich et al. does not include a cleansing surfactant and relies upon the nonionic thickening agent, e.g., a polymer, to suspend the water-insoluble ingredients. The present composition cleans and conditions the hair and does not require a thickener to suspend the conditioning agent. Bolich, Jr. et al. U.S. Pat. No. 4,902,499 discloses silicone polymer-containing compositions, wherein a surfactant or a fatty amine salt can be included as an optional ingredient. Bolich U.S. Pat. No. 4,374,825 discloses a hair conditioner including a volatile conditioning agent (i.e., a silicone or hydrocarbon), a nonionic water-soluble polymer and a quaternary ammonium compound or salt of a fatty amine.
Zofchak U.S. Pat. No. 4,548,810 discloses tertiary amine salts of fatty acids, wherein the fatty acid has an alkyl group of about eight to about 22 carbon atoms. The tertiary amine salts are used in cosmetic, toiletry and cleaning products, such as anionic surfactant-based shampoo products. European Patent Publication No. 0 252 551 discloses a phosphate ester or carboxylate salt of a tertiary amine used in a fabric softening or a detergent composition.
Several patents, including Caswell et al. U.S. Pat. No. 4,913,828 and European Patent Publication 0 294 893, disclose composites including a wax and an ion-pair comprising an alkyl amine or an imidazoline and an anionic surfactant, wherein the amine is a secondary or a tertiary amine. The ion pair is a chemically distinct species from either the amine or the anionic surfactant. Other patents disclosing an amine-anionic surfactant ion pair include Caswell et al. U.S. Pat. No. 4,857,213; Mermelstein et al. U.S. Pat. No. 4,844,824; and Mao et al. U.S. Pat. No. 4,915,854. Woodward et al. U.S. Pat. No. 4,392,965 discloses a laundry softener comprising a water-insoluble ion-pair compound comprising a carboxylate anion having at least ten carbon atoms and a quaternary ammonium compound having at least two carbon chains with at least twelve carbon atoms each.
A need still exists, however, for improved compositions that condition the hair, i.e., render the hair more manageable, and simultaneously clean the hair. Consequently, the present invention is directed to shampoo-conditioner compositions including a cleansing surfactant and a water-insoluble primary amine, wherein the shampoo-conditioner composition does not exhibit cationic-anionic incompatibilities, does not include additional water-insoluble conditioning agents (such as a silicone), but conditions the hair as well as present-day conditioning compositions. A present shampoo-conditioner composition effectively resists phase separation because of the presence of a sufficient amount of a suitable acid.
As will be demonstrated more fully hereinafter, a shampoo-conditioner composition, comprising: (a) a cleansing surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant and combinations thereof; (b) a water-insoluble primary amine having about fourteen to about twenty-two carbon atoms; and (c) a sufficient amount of a suitable acid; in (d) a carrier comprising water, effectively cleans the hair and, surprisingly, conditions the hair as well as compositions specifically designed to condition previously-shampooed hair.